Depending on working principles, common touch panels are classified into resistive touch panels and capacitive touch panels. When a user touches a surface of a capacitive touch panel with a finger or a conductive object, the capacitive touch panel would have a capacitance change at the touched site accordingly. The touched position can thus be determined in response to the sensed capacitance change. So far, a so-called two-dimensional capacitive touch panel has been the mainstream technology in the market. Capacitive touch panels have advantages over resistive touch panels, which perform press-sensing operations, for less material damage and capability of multi-touch sensing operations.
However, when operating a conventional capacitive touch panel, the user cannot feel the activation of a key as the key does not actually move in response to the touch. Furthermore, since in the manufacturing process of a conventional two-dimensional capacitive touch panel, it is necessary to take several steps to isolate the two sets of sensing pads in an interleaved portion of each other to form a capacitive sensing component matrix, the manufacturing cost is relatively high. Moreover, it is difficult to integrate such a touch panel into a smartphone or tablet computer structure.